The present invention relates to an image forming method using a charged particle beam, and a charged particle beam apparatus. In particular, the present invention relates to an image forming method and a charged particle beam apparatus capable of suppressing the influence of charging.
If an electron beam is applied to a sample, secondary electrons are generated. In scanning electron microscopes, an observed image on the surface of the sample is obtained using a phenomenon that the quantity of generation of secondary electrons changes depending upon the shape of the sample. In conventional scanning electron microscopes, scanning is conducted in the horizontal direction, i.e., in the raster direction in the screen every line (every horizontal line in the screen). The order of scanning lines is a descending order from the top to the bottom in the vertical direction in the screen.
In the scan scheme according to the conventional technique, raster scanning is conducted successively from the top to the bottom in the vertical direction in the screen. In the vertical direction, therefore, inclination is often generated in the charging phenomenon generated by electron beam radiation.
In other words, when a certain line is being scanned, charge remaining on a line already scanned immediately before affects the primary electron beam and the secondary electron beam in scanning, changes their trajectories, and distorts a finally obtained sample image.
In JP-A-2005-142038, it is described to reduce the influence of charging by conducting interlaced scanning using the charged particle beam.